(1) A collective term for chemical compounds containing nitrogen and oxygen. The two most common oxides of nitrogen found in the atmosphere are nitric oxide (NO) and nitrogen dioxide (N2). Nitrogen oxides are typically created during combustion processes. (2) Chemical compounds containing nitrogen and oxygen which react with volatile organic compounds, in the presence of heat and sunlight to form ozone. It is also a major precursor to acid rain. Nationwide, approximately 45 percent of NOX emissions come from mobile sources, 35 percent from electric utilities, and 15 percent from industrial fuel combustion.

This definition is in context to Sanitation. See more contextual defintions for Nitrogen Oxides (NOx).